Rollstand drive



Aug. 24, 1965 o. v. DUTRO ETAL 3,202,375

ROLLSTAND DRIVE Filed Nov. 6, 1962 INVENTORS,

ORV/1.45 1 00720 SHERMAN H. HEWSON United States Patent 0 3,202,376RfiLLSTAND DRIVE (lrviile V. Dutro, 5068 N. Commonwealth, and ShermanHewson, 640 Knight Way, both of La anada, Calif.

Filed Nov. 6, 1962, er. No. 235,889 24 @laims. ((il. 242-75.ll)

This invention relates to a rollstand drive and control for rotating aroll of web material to feed the material at a controlled rate of speed,and at a proper tension.

Particularly in the printing industries, where rolls of paper are fedinto a printing press, it is necessary to keep the tension of thematerial close to a constant value, as well as to feed the material atthe rate demanded by the press. Substantial deviations in tension willresult in portions of the printed material being out of register whichis particularly undersirable in color work, and failure to feed at pressspeed can cause tearing or wrinkling of the web.

Maintaining close speed and tension control over a heavy roll ofdecreasing weight and increasing angular velocity is inherentlydiificult. When a roll is nearly exhausted, it is light and tends tooverspeed and otherwise behave erratically. When the roll is new andheavy, its inertia tends to keep it turning at a rate which might beeither too fast or too slow. Both of these conditions can lead tovariations in rate and tension. Numerous rollstand drives and controlshave been provided which have as their desired objective the closecontrol over feed rate and tension of paper, foil, and like webmaterial. In general they exert control by exerting a braking force onthe core of the material. These and other types of controls requireconstant care, attention, and adjustment.

It is an object of this invention to provide a rollstand drive andcontrol which is inherently self-correcting, and which operates as arunning brake control at the surface of the roll, thereby avoiding thevariations and corrections which arise from change in angular velocityof the roll when control is exerted at the core.

It is a further and optional object of this invention to provide adevice wherein the roll is stable and rotates under close control, evenwhen paying out the last portion of the material which it carries.

A device according to this invention includes an outfeed drive whichengages the material at a location spaced from the roll, which outfeeddrive exerts the demand for material from the roll. The outfeed drive isusually driven by the press itself. Support means at least partiallysupports the roll. the roll, and preferably derives power from the pressthrough a transmission which can be set to drive the roll so that thelinear speed of the periphery is just a bit slower than that demanded bythe outerfeed drive, The support means and drive means are so disposedand arranged that one of them is movable relative to the other so as tovary the normal force with which the roll and drive means are broughttogether, whereby the amount of slippage between them is variablyadjustable. Adjustment means is adapted variably to adjust the forceexerted between the roll and the drive means by moving the movable oneof the support and drive means. The web is drawn from the roll and movedtoward the outfeed drive through a loop formed over a pair of fixedparallel rollers and a movable sensing roller.

A control means responsive to the position of the sensing roller isprovided for variably adjusting the adjustment means whereby an increaseor decrease in the loop length caused by a diderential between the rateof demand and that of supply causes the sensing Drive means contactsfreezers roller to lower or to raise, and the adjustment means toadjustably vary the force between the roll and the drive means, therebypermitting less or more slippage between the roll and drive means, withthe objective of permitting the outfeed drive to pull oi the web at thedesired rate and tension.

According to a preferred but optional feature of this invention, thedrive means comprises belts which engage and support at least portion ofthe periphery of the roll, and the adjustment means comprises apistoncylinder assembly responsive to a fluid pressure determined by theposition of the sensing roller.

The above and other features of this invention will be fully understoodfrom the following detailed description and the accompanying drawings inwhich:

FIG. 1 is a side elevation, partly in cutaway crosssection and partly inschematic notation, showing the presently preferred embodiment of theinvention;

FIG. 2 is a partial left-hand end view of FIG. 1; and

FIGS. 35 are fragmentary side elevations of alternate embodiments of theinvention.

In FIG. 1, a roll iii of Web material, such as a paper web for aprinting press, is at least in part supported by support means ii. Inthis embodiment, the support means comprises a pair of base journals 12,13, and a pair of swing arms 14*, 15 pin-jointed thereto. The centralshaft 16 of the roll is held in bearing 17 in the swing arms, spacedfrom the journals. The roll axis normally stands to one side of aperpendicular line drawn up from the base journals, so that the rollstendency is to move downwardly toward the ground, and more particularlyto bear against friction drive means 29.

The presently preferred embodiment of drive means 2% comprises threedrive belts 21, 22, 23, looped around shafts 24 and 25. Shaft 24 isdriven by the press drive through a manually adjustable transmission 27,whose output speed relative to motor input speed is adjustable. At leasta portion of the periphery of the roll is engaged by the drive belts,and the drive means supports a portion of the weight of the roll.

Web material 3% is withdrawn from the roll in the direction indicated byarrow 31. The demand for the web material is exerted by an outfeed drive32, which comprises two driven rolls 33, 34 which engage opposite sidesof the paper. The rolls are ordinarily driven by the press or Whateverdevice receives the web for processing.

Between roll lit and the outfeed drive, two fixed parallel rollers 35,3d are mounted to the frame. A sensing roller 37 is located so that theweb forms a loop 33 between the two fixed rollers, the length of whichis determined at least in part by the relative linear velocities of thematerial at roll Ill and at the outfeed drive 32. All rollers in thedevice are parallel to the axis of the roll.

Preferably, but not necessarily, the sensing roller is supported so thatits weight tends to move it downwardly. It could, of course, instead besupported and biased sidewise or even upwardly by springs or byfluidactuated cylinders to change the direction of the loop. In theillustrated embodiment of the invention, the sensing roller is supportednear the free ends of two pivot arms ill, which are joined by pins 41 tothe frame of the machine. Alternatively, the sensing roller could bemounted in upwardly extending slots or brackets in the side frame. It ismerely important that the sensing roller be movable in response to webtension.

One of the pivot arms carries a cam 42 with an actuating surface 43thereon. The sensing roller is supported by the loop in the illustratedembodiment and the ten sion at the loop is at least in part determinedby the weight of the sensing roller.

An adjustment means 55 comprising two pistoncylinder assemblies 46, 47is mounted to support means 11. Two brackets 48, 49 hinge-joint thecylinders to the base. The piston rods are held at joints t), 51 to theswing arms at points spaced from brackets 48', 49.

Control means for controlling the position of the adjustment meansincludes a first bleed-type pressure regulator 55 mounted to the machineframe beneath the cam. It receives pressure from a pump or compressor56. The regulator includes a stem 57, an inlet port 58, an outlet portas, and an exhaust port 6%). Regulators of this type are well known.They receive pressure from a pressure source and are capable ofmaintaining a regulated pressure at the outlet port in the range betweenambient atmospheric pressure and the maximum pressure of the supply. Nodetailed disclosure of the construction of such a regulator is necessaryhere, because such details form no part of this invention. Suiiice it tosay that the farther down the sensing roller moves, the farther down isthe stem 57 of the regulator moved, and the lower is the pressureproduced by the regulator and supplied from the outlet port to region 61of both of the piston-cylinder assemblies. The pressure produced mayapproach atmospheric. Bleeding off of pressure from regions 61 to lowerthe same is accomplished by passing some fluid from these regionsthrough the exhaust port. As the sensing roller and the stem moveupwardly, the pressure produced by regulator 55, and provided to regions61 increases.

A second bleed-type pressure regulator 62 receives fluid under pressurefrom the same source as the first regulator, and also includes an inletport 64, outlet port 65, and exhaust port 66. The outlet port 66 is connected to region 67 of both piston-cylinder assemblies. The secondregulator is adjustable, but not as a function of the sensing rollerpressure. Its purpose is similar to that of an accumulator in that itprovides and maintains a constant pressure in regions 67. it willthereby be seen that the pressure maintained in regions 67 is a constantforce tending to press the roll downwardly toward the drive means, whilethe force produced by regulator 55 variabiy ofisets this force and theweight of the roll, the adjustment means thereby partially assuming aburden of the roll which otherwise would be assumed by the drive means.The arrangement could, of course, be reversed by applying a higherstatic pressure to regions 61, and varying the pressure in regions 67with regulator 55, instead of vice versa as shown, by reversing the camoperation.

Bias means 119 forces the sensing roller against the loop with aregulable, constant force. The bias means comprises two piston-cylinderassemblies 111 mounted to pivot plate 112 on the side frames of themachine. The piston rods 113 are pinned to the pivot arms.

A fluid conducting line 114 conducts fluid under pressure from source 56to a bleed type pressure regulator 115. This regulator has the propertyof keeping its downstream side at a constant adjusted pressure, so longas the adjusted pressure lies between atmospheric pressure and pressurefrom supply 56.

Valve 115 discharges into regions 116 on the opposite sides of pistons119 from the pivot arms, there being one of these assemblies for eachpivot arm. A gauge 12% is teed into the line from valve 115. This gaugemay be calibrated to read in units of force load on the loop. The forceis, of course, directly proportional to pressure from valve 116, takinginto account the constant weight of the sensing roller and pivot arms.Valve 115 provides a simple means for finely adjusting the web tension.

FIGS. 3-5 illustrate alternate means of accomplishing the objectives ofthe device of FIG. 1. In FIG. 1, the force exerted between the roll andthe friction drive means is determined by the adjustment means whichshifts the roll toward and away from the drive means,

reducing the normal force between them by assuming more of the weight ofthe roll itself. FIG. 3 illustrates a device in which the same objectiveis accomplished, but in which the roll (and its support means) isunmovably mounted, while the drive means is relatively movable, insteadof vice versa.

FIGS. 4 and 5 illustrate a different type of friction drive means. Inthe system of FIGS. 1 and 3, the drive means is a belt system. In FIGS 4and 5 it is a drive wheel.

In PEGS 35, the numerals of components of the system of FIG. 1 are usedso far as the components are common, it being understood that thecomponents of FIGS. 3-5 are adapted for direct replacement of thefunctionally similar parts in FIG. 1.

FIG. 3 illustrates roll it? mounted to a fixed journal bearing 1%. Theroll rotates around its axis 161, but the axis is not laterallyshiftable, as it is in FIG. 1. Friction drive means includes a pair ofbase journals Iitid at opposite sides of the rollstand and a drivesupport arm 107 pin-jointed to each of the journals. The drive supportarms swing in the directions indicated by arrow 1&8. Shafts 24, 25, andbelts 21-23 are mounted to arms 107 so that the belts can be moved withvarying force against the roll by moving them toward and away from theroll by means of swinging arms 1%7.

Adjustment means 45 moves arms 1 3 7 instead of the support means. Inthis system, greater force between roll and drive means is obtained byincreasing the pressure in region 61, instead of decreasing it. Thisreversal of pressure direction can be secured either by reversing thecam, or by reversing the output of the valves with respect to stemmovement, or by reversing line connections to regions 61 and 67. Suchrearrangements of fluid flow are Well within the skill of any personlikely to use this device.

Drive means 165 friction drives the belts from the transmission as inFIG. 1, the only major difference residing in the mounting of shaft 25.

In FIG. 4, the rollstand construction is identical to that of FIG. 1,except that in place of drive means 20, which includes drive belts,different friction drive means is provided which utilizes a roller 131.The roller is mounted to shaft 24, and may either be a long cylinder, orone or more individual driven wheels carrying tires, keyed to the shaft.

FIG. 5 illustrates friction drive means 132 comprising a cylinder orwheels as in FIG. 4 mounted to drive support arms 1G7, and otherwiseadapted to drive the roll as in FIG. 3.

Slippage between cylinders or wheels can be controlled as with belts, asillustrated by FIGS. 4 and 5.

In the operation of the device of FIG. 1, the press is started,.whichstarts the outfeed drive and transmission 27. The transmission is set todrive the roll periphery at a speed somewhat slower than the outfeeddrive demands. The roll drive will then operate as a running brake, andthe outfeed drive will obtain the web it demands by pulling it off theroll, thereby slipping the roll on the belts. This pull on the webplaces the web under tension, and the tension is a function of the forceit takes to secure the necessary slippage.

The second pressure regulator is manually set at ahigher-than-atmospheric level, and the first pressure regulator, whichis controlled by the cam, is set relative to the cam and sensing rollerso that, when the loop is of the precisely correct length and tensionfor operation, the pressure passed by it counterbalances suflicient ofthe pressure in region '67 and thereby supports enough of the rollWeight, that the slippage rate between the roll and the drive means willenable the outfeed drive to obtain the web it demands at the properspeed.

At the outset, when the roll is heavy, it turns quite stably on thebelts and without substantial bouncing, so that roll stabilization isnot a great problem. However,

the inertia is then at its maximum value, and the system must beprotected from the over-running by coasting of the roll in case thepress demand rate diminishes, or in case the press should suddenly beshut down. This device does inherently provide this protection. Becausethe device is a running brake, and moves at a speed quite close to thatof the roll, in contrast to core brakes which are stationary, itmaintains a closer control.

Should the roll be turning at a speed faster than that demanded by theoutfeed drive, the loop will slacken, and the sensing roller will movedownwardly. It is necessary then to slow down the roll. To do this, thecam will depress the stem of the first pressure regulator. This willlower the pressure in region 61, which will cause the support means tomove clockwise in FIG. 1, thereby reducing the portion of the weight ofthe roll which the adjustment means carries and which formerly was borneby the support means. That is to say, normal force exerted by the rollon the drive means is increased. This is accomplished by permitting theroll to hear more heavily on the drive means. The increased frictionalengagement between the belts and the roll causes the drive belts tobrake the roll to bring its rate closer to that of the drive means,because less slippage is possible. This causes the loop to tighten upand shorten, and the sensing roller to rise. As the sensing rollerrises, the cam backs away from the stem, thereby raising the pressureemanating from the first regulator, and the pressure in regions 61increases. More of the weight of the roll is then carried by the supportmeans as the swing arms move counter-clockwise, and move the roll, sothat it bears less firmly on the drive belts, which is to say that thenormal force between them decreases. Greater slippage can thereforeoccur. Obviously, in this arrangement, there is a stable position of thesensing roller at which tension and rate are properly set, and thissystem hunts for it and then stably remains there, subject to adjustingitself for varying conditions during a run. The functions are undercontrol of the sensing roller. Varying the sensing roller weight, orvarying the presure from valve 115, changes the tension of the web, andthe system automatically adjusts itself to the new force conditions.

Toward the end of the roll, its radius is smaller, so that there will beless peripheral contact between the belt and the roller, and also lessWeight thereon. Excessive slippage between the drive means and the rollmight then occur. Also, there is inherently a greater tendency for theroll to bounce around when it is light and supported on belts as shown.Excessive slippage is equivalent to a substantial speeding up of thesupply rate, or lessening of the tension, both of which will cause theloop to lengthen, and the pressure from the first regulator to drop,ultimately to a value less than that supplied by the second regulator,thereby reversing the direction of bias of the adjustment means andcausing the roll to be pressed more firmly against the belts by theadjustment means. This not only decreases the slippage, but stabilizesthe roll against bouncing by forcing it against the drive belts. Thedevice is thereby capable of reversing its counterbalancing action toforcibly cause contact between the roll and the belts, as well as tomaintain the proper slippage rate for correct tension, thereby tostabilize the roll, maintain a proper rate of rotation, and maintain thetension at a desired value.

The transmission output rate is usually not changed during a run, and isnot under control of the sensing roller, The drive belts acts as brakes,and the variability is achieved by varying the slippage rate. However,the transmission can readily be fine-tuned in operation by manualadjustment.

The device of FIG. 3 operates in the same manner as that of FIG. 1,except that the support means does not move, and the drive means does.In this embodiment, Weight of the roll is not transferred to theadjustment means in the same sense as in FIG. 1, but the normal forcebetween the roll and the drive means is varied in precisely the samemanner. The drive means is driven by the transmission. The direction offorce in the adjustment means is reversed as aforesaid, because toincrease the force on the roll in FIG. 1 called for a decrease ofpressure in regions 61, while in FIG. 3, it calls for an increase.

The devices of FIGS. 4 and 5 operate the same as those of FIGS. 1 and 3,respectively, except that their single shafts carry wheels or cylindersinstead of belts, but the slippage situation is the same. The belts forboth embodiments which use them will ordinarily be of leather. Thewheels will ordinarily carry nonmarking rubber tires.

All drive means shown are disposed beneath the roll. However, they couldalso be located at any other portion or portions of the periphery of theroll, including atop the same, with only small and obviousrearrangements of parts, and proper selection of pressure direction onthe adjustment means. i

The device is inherently very simple, util zing only conventionalconstruction elements which are easily manufactured and easily repairedor replaced. It eliminates any need for close care and attention to corespeeds, such as is required in conventional core brake type rollstands,is simple to set up, and automatic in operation.

This invention is not to be limited by the embodiments shown in thedrawings and described in the description which are given by way ofexample and not of limitation, but only in accordance with the scope ofthe appended claims.

We claim:

1. A rollstand drive and control for turning a roll of web material tofeed the material at a controlled rate and tension, comprising: anoutfeed drive engaging the materia at a location spaced from the roll,which outfeed drive exerts a demand for material from the roll; supportmeans at least in part supporting the roll, the roll being rotatablysupported; friction drive means adapted to contact and turn the roll,said drive means operating at a constant speed; adjustment means adaptedto variably adjust the normal force between the roll and the drivemeans; a pair, of laterally spaced-apart, fixed parallel rollers, amovable sensing roller; material withdrawn from the roll passing overboth of said fixed rollers, and over said sensing roller to form a loopbetween the fixed rollers, and thence to the outfeed drive, whereby adifference in linear speed of material at the point of departure fromthe roll and at the outfeed drive changes the length of the loop, andthereby the position of said sensing roller; and control meansresponsive to the position of the sensing roller for variably adjustingthe output of the adjustment means, whereby variation in loop lengthpermits the: sensing roller position to change, causing the controlmeans to adjust the adjustment means and thereby the said normal forcebetween the drive means and the roll, thereby to adjust the slippagerate therebetween, and cause the roll speed to change to restore theloop to a desired length indica tive of correct tension and linearspeed.

2. Apparatus according to claim 1 in which the adjustment meanscomprises a pressure-actuated piston-cylinder assembly, and in which thecontrol means comprises a valve responsive to the position of saidsensing roller for adjusting pressure supplied to said assembly whichtends to move the roll away from said drive means.

3. Apparatus according to claim 1 in which the support means and rollare movable toward and away from the drive means, the adjustment meansmoving the support means.

4. Apparatus according to claim 3 in which the drive means comprisesbelts engaging a portion of the periphery of the roll.

5. Apparatus according to claim 3 in which the drive means comprisescylindrical structure engaging a portion of the periphery of the roll.

angers 6. Apparatus according to claim l in which the drive means ismovable toward and away from the support means and roll, the adjustmentmeans moving the drive means.

7. Apparatus according to claim 6 in which the drive means comprisesbelts engaging a portion of the periphery of the roll.

8. Apparatus according to claim 6 in which the drive means comprisescylindrical structure engaging a portion of the periphery of the roll.

9. A rollstand drive and control for turning a roll of web material tofeed the material at a controlled rate and tension, comprising: anoutfeed drive engaging the material at a location spaced from the roll,which outfeed drive exerts a demand for material from the roll; supportmeans at least in part supporting the roll, the roll being rotatablysupported, friction drive means adapted to contact the roll, bear atleast a part of the weight of said roll, and turn the roll, said drivemeans operating at a constant speed; adjustment means adapted tovariably adjust the proportion of the weight of the roll which iscarried by the drive means by assuming some of the weight whichotherwise would be carried by the drive means and thereby to adjust thenormal force between them; a pair of laterally spaced-apart, fixedparallel rollers, a movable sensing roller; material withdrawal from theroll passing over both of said fixed rollers; and over said sensingroller to form a loop between the fixed rollers, and thence to theoutfeed drive, whereby a difference in linear speed of the material atthe point of departure from the roll and at the outfeed drive changesthe length of the loop, and thereby the position of said sensing roller;and control means responsive to the position of the sensing roller forvariably'adjusting the adjustment means, whereby increase or decrease inloop length permits the sensing roller to lower or raise, and theadjustment means to assume a lesser or greater proportion of the rollweight, thereby permitting less or more slippage between the roll .andthe drive means as a function of the said normal force, thereby enablingthe roll to slow down and shorten the loop or to speed up and lengthenthe loop, all respectively.

10. Apparatus according to claim 9 in which the adjustment meanscomprises a pressure-actuated piston-cylinder assembly, and in which thecontrol means comprises a valve responsive to the position of thesensing roller for adjusting pressure supplied to said assembly whichtends to move the roll away from said drive means.

11. Apparatus according to claim 10 in which said valve is a bleed-typepressure regulator valve, and in which the other side of the saidassembly is adapted to receive fluid under constant pressure, wherebylowering of the pressure from the regulator below that of the saidconstant pressure enables the roll to be pressed against the drivemeans.

12.. Apparataus according to claim 11 in which the drive means comprisesdriven belts which embrace a por tion of the rolls periphery.

13. A rollstand drive and control for turning a roll of web material tofeed the material at a controlled rate and tension, comprising: anoutfeed drive engaging the material at a location spaced from the roll,which outfeed drive exerts a demand for material from the roll; supportmeans at least in part supporting the roll, the roll being rotatablysupported; friction drive means adapted to contact the roll, bear atleast a part of the weight of said roll, and turn the roll, said drivemeans operating at a constant speed; adjustment means adapted tovariably adjust the proportion of the weight of the roll which iscarried by the drive means by assuming some of the weight whichotherwise would be carried by the drive means and thereby to adjust thenormal force between them; a pair of laterally spaced-apart, fixedparallel rollers; a sensing roller, material withdrawn from the rollpassing over one of said fixed rollers, under said sensing roller, overthe other of said fixed rollers to form a loop, and thence to theoutfeed drive, whereby a difference in linear speed of the material atthe point of departure from the roll and at the outfeed drive change thelength of the loop, and thereby the position of said sensing roller; andcontrol means responsive to the position of the sensing roller forvariably adjusting the adjustment means, whereby increase or decrease inloop length permits the sensing roller to lower or raise, and theadjustment mean to assume a lesser or greater proportion of the rollweight, thereby permitting less or more slippage between the roll andthe drive means as a function of the said normal force, thereby enablingthe roll to slow down and shorten the loop or to speed up and lengthenthe loop, all respectively.

14. Apparatus according to claim 13 in which the adjustment meanscomprises a pressure-actuated pistoncylinder assembly, and in which thecontrol means comprises a valve responsive to the position of thesensing roller for adjusting pressure supplied to said assembly whichtends to move the roll away from said drive means.

15. Apparatus according to claim 14 in which said valve is a bleed-typepressure regulator valve, and in which the other side of the saidassembly is adapted to receive fluid under constant pressure, wherebylowering of the pressure from the regulator below that of the saidconstant pressure enables the roll to be pressed against the drivemeans.

16. Apparatus according to claim 15 in which the drive means comprisesdriven belts which embrace a portion of the rolls periphery. I

17. Apparatus according to claim 15 in which the drive means comprisescylindrical structure which engages a portion of the periphery of theroll.

18. A rollstand drive and control for turning a roll of web material tofeed the material at a controlled rate and tension, comprising: anoutfeed drive engaging the material at a location spaced from the roll,which outfeed drive exerts a demand for material from the roll; supportmeans at least in part supporting the roll, the roll being rotatablysupported; friction drive means adapted to contact the roll, bear atleast a part of the weight of said roll, and turn the roll, said drivemeans operating at a constant speed; adjustment means adapted tovariably adjust the proportion of the weight of the roll which iscarried by the drive means by assuming some of the weight whichotherwise would be carried by the drive means and thereby to adjust thenormal force between them; a pair of laterally spacedapart, fixedparallel rollers; a sensing roller; a pivot arm rotatably and swingablysupporting said sensing roller, material withdrawn from the roll passingover one of said fixed rollers, under said sensing roller, over theother of said fixed rollers to form a loop, and thence to the outfeeddrive, whereby a ditference in linear speed of the material at the pointof departure from the roll and at the outfeed drive changes the lengthof the loop, and thereby the position of the pivot arm; and controlmeans operatively connected to the pivot arm and controlled by saidpivot arm for variably adjusting the adjustment means, whereby increaseor decrease in loop length permits the sensing roller to lower or raiseand the adjustment means to assume a lesser or greater proportion of theroll weight, thereby permitting less or more slippage between the rolland the drive means as a function of the said normal force, therebyenabling the roll to slow down and shorten the loop or to speed up andlengthen the loop, all respectively.

19. Apparatus according to claim 18 in which the adjustment meanscomprises a pressure-actuated piston-cylinder assembly, and in which thecontrol means comprises a valve responsive to the position of thesensing roller for adjusting pressure supplied to said assembly whichtends to move the roll away from said drive means.

Zil. Apparatus according to claim 19 in which said valve is a bleed-typepressure regulator valve, and in which the other side of the saidassembly is adapted to receive fluid under constant pressure, wherebylowering of the pressure from the regulator below that of the saidconstant pressure enables the roll to be pressed against the drivemeans.

21. Apparatus according to claim 18 in which the drive means comprisesdriven belts which embrace a portion of the rolls periphery.

22. Apparatus according to claim 21 in which the adjustment meanscomprises a double-ended piston-cylinder assembly and in which thecontrol means includes a first pressure regulator feeding one side ofthe assembly and Whose output pressure is governed by the position ofthe sensing roller, and a second pressure regulator which maintains thepressure on the other side of the piston at a constant above-atmosphericvalue.

23. Apparatus according to claim 22 in which a cam is regulated by theposition of the sensing roller to set the first pressure regulator.

UNITED STATES PATENTS 1,786,917 12/30 Oehmichen 242--75.5 2,098,422ll/37 Keen et al 242-4562 2,366,143 12/44 Cafirey 242-7542 X 2,670,9673/54 Huck 24-275.1 3,083,602 4/63 Obenshain 242-75 .43 X

RUSSELL C. MADER, Primary Examiner.

MERVIN STEIN, Examiner.

1. A ROLLSTAND DRIVE AND CONTROL FOR TURNING A ROLL OF WEB MATERIAL TOFEED THE MATERIAL AT A CONTROLLED RATE AND TENSION, COMPRISING: ANOUTFEED DRIVE ENGAGING THE MATERIA AT A LOCATION SPACED FROM THE ROOL,WHICH OUTFEED DRIVE EXERTS A DEMAND FOR MATERIAL FROM THE ROLLL; SUPPORTMEANS AT LEAST IN PART SUPPORTING THE ROLL, THE ROLL BEING ROTATAABLYSUPPORTED; FRICTION DRIVE MEANS ADAPTED TO CONTACT AND TURN THE ROLL,SAID DRIVE MEANS OPERATING AT A CONSTANT SPEED; ADJUSTMENT MEANS ADAPTEDTO VARIABLY ADJUST THE NORMAL FORCE BETWEEN THE ROLL AND THE DRIVEMEANS; A PAIR OF LATERALLY SPACED-APART, FIXED PARALLEL ROLLERS, AMOVABLE SENSING ROLLER; MATERIAL WITHDRAWN FROM THE ROLL PASSING OVERBOTH OF SAID FIXED ROLLERS, AND VOER SAID SENSING ROLLER TO FORM A LOOPBETWEEN THE FIXED ROLLERS, AND THENCE TO THE OUTFEED DRIVE, WHEREBY ADIFFERENCE IN LINEAR SPEED OFMATERIAL AT THE POINT OF DEPARTURE FROM THEROLL AND AT THE OUTFEED DRIVE CHANGES THE LENGTH OF THE LOOP, ANDTHEREBY THE POSITION OF SAID SENSING ROLLER; AND CONTROL MEANSRESPONSIVE TO THE POSITIN OF THE SENSING ROLLER FOR